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                [Usaco2011 Mar]Tree Decoration                </h1>
                <p>时间限制：10s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：259MB</p>			</div>
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                                <h3>题目描述</h3><p><p>Farmer John is decorating his Spring Equinox Tree (like a Christmas tree but popular about three months later). It can be modeled as a rooted mathematical tree with N (1 &lt;= N &lt;= 100,000) elements, labeled 1...N, with element 1 as the root of the tree. Each tree element e &gt; 1 has a parent, P_e (1 &lt;= P_e &lt;= N). Element 1 has no parent (denoted '-1' in the input), of course, because it is the root of the tree. Each element i has a corresponding subtree (potentially of size 1) rooted there. FJ would like to make sure that the subtree corresponding to element i has a total of at least C_i (0 &lt;= C_i &lt;= 10,000,000) ornaments scattered among its members. He would also like to minimize the total amount of time it takes him to place all the ornaments (it takes time K*T_i to place K ornaments at element i (1 &lt;= T_i &lt;= 100)). Help FJ determine the minimum amount of time it takes to place ornaments that satisfy the constraints.  Note that this answer might not fit into a 32-bit integer, but it will fit into a signed 64-bit integer. For example, consider the tree below where nodes located higher on the display are parents of connected lower nodes (1 is the root):</p>
<p><img border="0" src="../file/2197_0.jpg" alt="" /></p>
<p>Suppose that FJ has the following subtree constraints:</p>
<p><img border="0" src="../file/2197_1.jpg" alt="" /></p>
<p>Then FJ can place all the ornaments as shown below, for a total cost of 20:</p>
<p><img border="0" src="../file/2197_2.jpg" alt="" /></p>
<p>FJ要装饰一棵Spring Equinox树（N个节点，标号为1--N，1为根节点）。&nbsp;</p>
<p><img border="0" src="../file/2197_3.jpg" alt="" /></p></p><hr/><h3>输入格式</h3><p><p>* Line 1: A single integer: N  * Lines 2..N+1: Line i+1 contains three space-separated integers: P_i,         C_i, and</p>
<p>T_i</p>
<p>&nbsp;第一行：N -----代表N个节点 接下来N行 每行三个数P_i -----i的父亲节点 C_i ----以i为根节点的子树需要至少C_i个装饰品 T_i ----在i这个节点挂一个装饰品需要T_i的时间&nbsp;</p></p><hr/><h3>输出格式</h3><p><p>* Line 1: A single integer: The minimum time to place all the         ornaments</p>
<p>挂上所有装饰品所需要的总时间</p></p><hr/><h3>样例输入</h3><pre>5
-1 9 3
1 2 2
5 3 2
5 1 4
2 3 3
</pre><hr/><h3>样例输出</h3><pre>20
</pre><hr/><h3>提示</h3><p>没有写明提示</p><hr/><h3>题目来源</h3><p>Gold</p>
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